The ToolKIT, which is accessible from all pages of the site, outlines the three main analytical skills that TonalityGUIDE.com aims to develop. It also links to a short introduction to the study of tonality as well as a reminder of some basics (note and interval labels, clefs and transpositions).

Debussy (twentieth century 'impressionist' piano prelude)In this example, the sevenths do not follow voice-leading rules nor do they resolve to a chord a fifth below, except for the last one. This series of chords also contain ninths (marked in yellow) which likewise do not follow the voice-leading patterns of earlier eras. Without specific voice-leading and harmonic function, the sevenths and ninths are part of the basic sonority of the piece, in the same way that triads are in earlier styles.